When it comes to cannabis, there are a lot of myths and misconceptions floating around, especially about its impact on the brain. One of the most common (and concerning) claims is that cannabis use lowers IQ. But what if I told you that recent research is challenging this myth and showing a more nuanced reality?
In fact, occasional cannabis use is not linked to lower IQ—and in some cases, it’s even associated with higher cognitive functioning, particularly in certain groups like youth at clinical high risk (CHR) for psychosis. Let’s dive into the science and debunk some of these common cannabis misconceptions.
What the Research Really Says About Cannabis and IQ
Recent studies are shedding light on how cannabis impacts the brain, and the findings may surprise you:
1. Occasional Cannabis Use & Higher Cognitive Function
A recent study focusing on youth at clinical high risk for psychosis found that occasional cannabis users actually performed better on IQ tests than other groups, including frequent users and non-users. These occasional users also showed better social functioning, global cognitive health, and pre-morbid functioning (essentially how well a person functions before illness). They even experienced less severe symptoms compared to those who used cannabis more frequently.
Translation? Occasional cannabis use might not just not harm cognitive function—it might even have some surprising benefits for certain individuals.
Read the study here.
2. No Evidence of Cognitive Decline
Another study using a twin design (which is a cool way to control for genetic factors) found no significant evidence that cannabis use causes cognitive decline. This research supports earlier findings that occasional or moderate cannabis use is unlikely to hurt your brainpower.
In short, cannabis use may not lower IQ or cause cognitive deficits in normative users.
Check out the study.
3. Socioeconomic Status Might Be the Real Culprit
One of the most surprising findings in recent cannabis research is that socioeconomic status (SES) might actually be the underlying factor behind the perceived link between cannabis use and IQ declines.
Studies, including the influential Dunedin cohort study, suggest that any apparent connection between cannabis use and lower IQ might be due to confounding variables, such as a person’s background, access to resources, or educational opportunities, rather than cannabis use itself. In simpler terms, individuals from lower socioeconomic backgrounds might have fewer opportunities for cognitive development due to environmental and social factors, not because they use cannabis.
So, if you’ve heard that cannabis causes IQ drops, it’s worth considering other factors at play.
More details on this study here.
4. No Link Between Adolescent Cannabis Use and IQ Decline
For parents concerned about the effects of cannabis on their teenagers’ developing brains, here’s some reassuring news: recent studies show no direct link between adolescent cannabis use and long-term IQ decline or poor educational outcomes, provided other factors like cigarette smoking are taken into account.
Early research suggested that cannabis use in adolescence could negatively impact cognitive function, but these studies often didn’t adjust for key confounding factors. Once variables like cigarette use, socioeconomic status, and alcohol consumption were considered, the supposed link between cannabis and lower IQ became much weaker—or disappeared altogether.
This means that occasional or moderate cannabis use during adolescence, in isolation, may not be as harmful to cognitive development as previously feared. While it’s still important to approach cannabis use with caution, especially during the teenage years when the brain is still maturing, these findings suggest that moderate use may carry fewer risks than previously thought.
For a deeper dive into this research, you can check out the study here.
So, Does Cannabis Lower IQ?
The short answer is no—cannabis use doesn’t automatically lower IQ, despite long-held myths. The latest science paints a much more nuanced picture, particularly when we differentiate between occasional, moderate, and heavy use.
Occasional or moderate cannabis use, especially when done in controlled environments or for medical purposes, has not been shown to negatively impact cognitive ability in most people. In fact, as recent studies reveal, it might even be associated with better cognitive performance in specific populations. For example, youth at clinical high risk (CHR) for psychosis who occasionally use cannabis were found to have better pre-morbid functioning, higher IQ scores, and improved social functioning compared to both frequent users and non-users. This suggests that occasional cannabis use, when balanced, may not impair brain function and could potentially support certain cognitive benefits.
What About Heavy or Chronic Use?
It’s important to note that while occasional or moderate use may have minimal cognitive impact, heavy or chronic use of cannabis—especially during adolescence, when the brain is still developing—might pose risks. Frequent use has been linked to certain cognitive and emotional challenges, such as impaired memory, difficulty concentrating, and emotional dysregulation in some individuals. The key difference is frequency and age of use. Adolescence is a critical period for brain development, and frequent cannabis use during this time could interfere with that process.
For adult users, however, heavy use over long periods may also carry risks, though these are not always permanent. In some cases, the brain can recover once heavy cannabis use is reduced or stopped. What’s clear is that the risks are more significant with long-term, frequent use than they are with occasional use.
Better Cognitive Performance in Certain Groups
Interestingly, research has shown that cannabis may actually support better cognitive performance in specific groups, like youth at risk for psychosis. Occasional cannabis users in these studies demonstrated better results on IQ tests and social functioning compared to frequent users. This suggests that cannabis could potentially play a role in modulating symptoms or supporting cognitive function in certain neurological or psychiatric conditions when used sparingly.
In summary, moderate, occasional cannabis use does not seem to lower IQ and may even have cognitive benefits for some. However, as with most things, balance is key. For those using cannabis responsibly and in moderation, the potential for cognitive harm is minimal—far from the alarmist narratives we’ve often heard.
What Does This Mean for You?
If you’ve been cautious about using cannabis due to concerns about your IQ, these findings should give you some peace of mind. Moderate, occasional cannabis use appears to have minimal impact on cognitive function, and it may even help reduce stress and improve social functioning, which can enhance your mental clarity.
Of course, everyone is different. What works for one person may not work for another, so it’s always important to use cannabis responsibly and be mindful of your own health and wellness.
Final Thoughts
Cannabis continues to be a topic of intense research, and while there’s still a lot to learn, the evidence we have so far suggests that moderate cannabis use won’t tank your IQ. Whether you’re curious about cannabis or a regular user, it’s important to stay informed with the latest science and make decisions that best support your overall well-being.
Got questions or thoughts on this? Drop them in the comments below—let’s keep this conversation going!
